The Big Badlands

One hundred million years ago this region was under a vast inland sea and 40 million years later the uplift of the Rocky Mountains and the Black Hills pushed back these waters and the mud at the bottom of that sea became the black shales of western South Dakota. As these mountains slowly rose, large streams flowed east, carrying much rock and silt, deposited here as sandstones and clays, on the black shale, in their channels and flood plains.

Some horizons also contain volcanic ash, blown in from the far west. Wind and water have since carved this 600 foot of stream deposits into our picturesque Badlands. In the Oligocene age, 30 million years ago, numerous mammalian and a few reptilian forms existed in the warm temperature climate of the epoch.

Dying, many of their bones petrified under the moist sediments and these fossils are now being slowly exposed by rain and wind. Some of these animals, the three-toed horse, tiny camel and deer, huge pigs and saber tooth cats are distant relatives of modern animals; others, like the oreodonts and bulky titanotheres became extinct while most numerous in this age.

Today the Big Badlands represents the most important Oligocene deposits known to man and thousands of fossils have been yielded to the science of paleontology. They first became known to man in 1830, when the first great western trail from Ft. Tecumseh (Pierre) to Ft. William (Laramie) penetrated the Badlands by the pass South of Scenic and to the scientific world when Alexander Culbertson made a trip into them and sent out a cartload of fossils in 1843.